Heat dissipating elements such as semi-conductor heat-sinks can be of various profiled forms but often comprise a predetermined length cut from a profiled extruded metal member. The profiles of the extruded members used for forming such elements are dictated by the profiles of the dies through which the members are extruded and the profile of an element formed from an extruded member varies across only its width transverse to its direction of extrusion.
U.S. Pat. No. 4,884,331 refers to a process for forming a semi-conductor heat-sink by cross-cut gang sawing in a transverse direction a longitudinally extending profiled extruded metal member. The extruded member comprises a longitudinally extending sheet-form member having a plurality of longitudinally extending transversely spaced ribs upstanding therefrom. By cross-cut sawing the ribs depthwise in a transverse direction at locations along their length and then parting off a predetermined length from a processed portion of the extruded member, a semi-conductor heat-sink comprising a base member having a plurality of transversely spaced rows of longitudinally extending rib portions is formed. The arrangement of the rib portions enhances the heat dissipating efficiency of the heat-sink so formed.
A disadvantage of this process for forming a semi-conductor heat-sink is that it is relatively expensive and slow. The cross-cutting of the ribs creates sharp burrs on the sawn edges which must be removed before the heat-sink can be utilized. The additional step of removing the burrs adds to the expense of the manufacturing process.
Because the rib portions of the heat-sink are formed by cross-cut gang sawing the ribs of an extruded member, the rib portions of adjacent rows are transversely aligned which may limit the heat dissipating efficiency of the heat-sink.
It is an object of the present invention to obviate and mitigate the aforesaid disadvantages.